1. Field of the Invention
The present invention relates to a system and a method for assisting visibility of a driver, and more particularly, to a system and a method for assisting visibility of a driver capable of implementing a nighttime color image required to recognize a pedestrian and an image of displaying a lane required to warn a lane departure using a single camera module.
2. Description of the Related Art
In recent vehicle technologies, in order to improve convenience and safety of drivers during drive of vehicles, various systems in which cameras are installed at front, rear, right, and left sides of the vehicles to check images through displays of dashboards in front of driver's seat have been researched and already started to be applied.
As one of the systems for consulting convenience of drivers, a night vision system (NVS), which is an apparatus for assisting visibility of a driver during drive of a vehicle in a dark environment, such as a nighttime drive, radiates infrared light forward from a vehicle and photographs the infrared light to provide an image to the driver.
A horizontal angle of view of a camera module required in the NVS is about 17° and requires resolution of a video graphic array (VGA) of 640×480 or more to recognize a pedestrian.
Meanwhile, in addition to the NVS, another one of the systems for consulting convenience of drivers, a lane departure warning system (LDWS) is provided as a safety apparatus to detect a road image in front of a vehicle from a camera attached to the vehicle to recognize the lane where the vehicle is currently running, and alarm an alert sound if the vehicle is going to depart from the lane due to the driver's carelessness or drowsy driving.
Since the camera module required in the LDWS must recognize both of far and near lanes in front of the vehicle, a horizontal angle of view of the camera module is needed to be about 40° that is larger than that required in the NVS. In addition, since it is needed to recognize only the lane formed in a simple pattern, it is needed to satisfy resolution of a quarter video graphic array (QVGA) of 320×240 that is lower than that required in the NVS.
Accordingly, in order to implement the NVS and the LDWS using a single camera module, a horizontal angle of view of a lens of about 40° or more and resolution of a VGA of 640×480 or more are needed.
However, headlamps of the vehicle use a yellow light having a wavelength of 555 nm with good sensitivity to human's eyes. In order to prevent a blooming phenomenon in which a night vision image is saturated due to light of headlamps of the driver's vehicle and a vehicle, which is coming from an opposite side, infrared (IR) pass filters through which only light of 650 nm or more passes are installed in the most camera modules used in the NVS. In addition, in order to avoid deterioration of image quality due to infrared light departing from a visible region, IR cut filters are installed between lenses and image sensors of camera modules used in the LDWS to block infrared light.
For this reason, the camera module used in the NVS cannot implement a color image to recognize a color of the lane, and the camera module used in the LDWS cannot identify objects in a low illuminance environment. Accordingly, it is difficult to simultaneously implement the image representing the lane and the image representing the pedestrian during the nighttime driving using the single camera module. Therefore, in order to simultaneously implement the image representing the lane and the image representing the pedestrian during the nighttime, the respective camera modules must be used to be correspondingly required in the respective systems. As a result, implements of the system for assisting visibility of the driver are costly.
In addition, when the NVS shows an image representing a pedestrian, since the IR pass filter is disposed in the camera module, a black and white image is implemented to make it difficult for the driver to see the display and discriminate the pedestrian.